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Delta Checks for PT, PTT, Fg, and D-dimer

Lisa Ledford at Duncan Regional Hospital asks, Would you be willing to share your δ-check values for PT/INR, PTT, fibrinogen, and D-dimer?

Hi, Lisa, I checked with Warren Varden at UAB, who confirmed that we don’t use delta checks. Our special coagulation staff carefully review results and communicate with our inpatient and outpatient units. They are able to discern when there is a change in therapy or a faulty specimen collection. However, some of our participants may provide us with their δ-check systems. Please respond here.

Comments (3)
Specimen Management
Jan 9, 2013 12:25pm

Hello, I have a question, while administering Xarelto (rivar
Hello, I have a question, while administering Xarelto (rivaroxaban), will this give a false positive result on lupus anticoagulant tests?

Jan 8, 2013 2:44pm

I have used delta checks for INR testing, if the result vari
I have used delta checks for INR testing, if the result varied by more than 2.0 from previous the analyser would automatically retest the INR. The computer interface would calculate the percentage difference between the two results. This turned out to be a really useful form of QA by showing us regular glimpses of analyser precision. We were putting through approximately 200 INRs per hour and running QC every 2 hours. If the analyser precision deteriorated between our regular QC measurements we picked it up quickly.

Alan Neal
Jan 7, 2013 3:17pm

For coagulation we only delta check (critical result differe
For coagulation we only delta check (critical result difference) INR results for patients on oral anticoagulant therapy (OAT, Coumadin) a basic screen.
We have calculated significant difference check using Harris et al formulae:
Then critical variation = 2.77(A2 + B2)½
A = Analytical precision (CV %)
B = within subject biological variation (CV %).
Using this data we have calculated critical variation INR and this data is consistent with publications. We also used this approach with other haematological parameters.
*PS: I don’t believe reviewing every result gives any more quality, so long a pre-analytical check performed (HIL sample volume etc). The most significant error in INR determination we have seen in a very small no of cases relates to two half filled citrate tubes being pooled, with subsequent significantly prolonged INR (>10) and this can be detected by measuring Na level in tube.

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